“Cars were exploding, and I saw the [jet’s] tail sticking up, the engine in the street and debris everywhere.”

The twin-engine F/A-18D Hornet jet was approaching the Marine Corps Air Station Miramar – the setting of the movie “Top Gun” – when it nose-dived into University City just before noon, reducing houses in the middle-class neighborhood to rubble.

The $57 million supersonic jet, which witnesses saw flying as low as 400 feet, was only two miles from the base when it hurtled into one house. Pieces of the wreckage slid into two other homes.

Cars exploded after they were doused with jet fuel.

“Flames and black smoke were 300 feet in the air,” said Scott Bloom, a financial planner who was on his way to meet an elderly couple across the street from the crash.

“There was debris in the driveway and flames in the street. The next-door neighbors’ house was engulfed. I helped them to get out.”

Authorities said two children, a mother and a grandmother were believed to have been in one home the plane hit.

Three died and the fourth was unaccounted for.

A piece of the cockpit was discovered on the roof of a home, and one of the plane’s charred engines landed in the street.

Ten to 15 seconds before impact, the pilot ejected, landing about a half-mile from the crash site in a tree on a high-school field.

“It was just like in the movies,” Bloom said. “He shoots up like a cannon, a couple of hundred feet in the air.”

Jason Widmer, who was working nearby and rushed to the pilot’s aid, said the aviator was “a little shaken up” when he first got down from the tree, but otherwise seemed fine.

“The first thing he said to me, even before he said, ‘I’m OK,’ he said, ‘I hope I didn’t kill anybody,’ ” Widmer said.

Another witness speculated to a San Diego radio station that the pilot, a lieutenant in his 20s, might have been steering the plane toward a canyon to avoid the school.

Officials said the aircraft, had taken off from a carrier in a training exercise.

Shortly afterward, the pilot began experiencing problems, possibly engine trouble, and was ordered to make an emergency landing, according to the Los Angeles Times.

As the jet crossed over land, there may have been a “flameout” of the second engine, causing the plane to wobble and drop.